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Background:The prevalence of obesity is increasing in all countries, becoming a substantial public health concern worldwide. Increasing evidence has associated obesity with persistent pollutants such as the pesticide DDT and its metabolite p,p′-DDE.Objectives:Our objective was to systematically review the literature on the association between exposure to the pesticide DDT and its metabolites and obesity to develop hazard identification conclusions.Methods:We applied a systematic review-based strategy to identify and integrate evidence from epidemiological, in vivo, and in vitro studies. The evidence from prospective epidemiological studies was quantitatively synthesized by meta-analysis. We rated the body of evidence and integrated the streams of evidence to systematically develop hazard identification conclusions.Results:We identified seven epidemiological studies reporting prospective associations between exposure to p,p′-DDE and adiposity assessed by body mass index (BMI) z-score. The results from the meta-analysis revealed positive associations between exposure to p,p′-DDE and BMI z-score (normalβ=0.13 BMI z-score (95% CI: 0.01, 0.25) per log increase of p,p′-DDE). Two studies constituted the primary in vivo evidence. Both studies reported positive associations between exposure to p,p′-DDT and increased adiposity in rodents. We identified 19 in vivo studies and 7 in vitro studies that supported the biological plausibility of the obesogenic effects of p,p′-DDT and p,p′-DDE.Conclusions:We classified p,p′-DDT and p,p′-DDE as “presumed” to be obesogenic for humans, based on a moderate level of primary human evidence, a moderate level of primary in vivo evidence, and a moderate level of supporting evidence from in vivo and in vitro studies. https://doi.org/10.1289/EHP527

Breast cancer (BC) is one of the most common causes of cancer in the world and the second leading cause of cancer deaths among women. Mortality is associated mainly with the development of metastases. Identification of the mechanisms involved in metastasis formation is, therefore, a major public health issue. Among the proposed risk factors, chemical environment and pollution are increasingly suggested to have an effect on the signaling pathways involved in metastatic tumor cells emergence and progression. The purpose of this article is to summarize current knowledge about the role of environmental chemicals in breast cancer progression, metastasis formation and resistance to chemotherapy. Through a scoping review, we highlight the effects of a wide variety of environmental toxicants, including persistent organic pollutants and endocrine disruptors, on invasion mechanisms and metastatic processes in BC. We identified the epithelial-to-mesenchymal transition and cancer-stemness (the stem cell-like phenotype in tumors), two mechanisms suspected of playing key roles in the development of metastases and linked to chemoresistance, as potential targets of contaminants. We discuss then the recently described pro-migratory and pro-invasive Ah receptor signaling pathway and conclude that his role in BC progression is still controversial. In conclusion, although several pertinent pathways for the effects of xenobiotics have been identified, the mechanisms of actions for multiple other molecules remain to be established. The integral role of xenobiotics in the exposome in BC needs to be further explored through additional relevant epidemiological studies that can be extended to molecular mechanisms.

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The aflatoxins (AFs), deoxynivalenol (DON), ochratoxin A (OTA) and zearalenone (ZEA) are mycotoxins produced by fungal species which can contaminate, alone or simultaneously, cereal-based raw materials. Usually, the higher mycotoxins concentrations in cereals are found in the external layers of the grain (bran). Nowadays bran is increasingly consumed for its high fibre concentration. The objectives of this study were determining the concentration of these mycotoxins in bran samples intended for direct human consumption and to study the influence of some characteristics of the samples that may affect the mycotoxins content, there are not studies about fibre for direct human consumption. 67 bran samples from shops and supermarkets from two different Spanish cities were analyzed, being 37 samples of wheat bran and the remaining of oat bran. The results showed a major presence of DON in the analyzed samples, with levels above the EU legislation in some samples. Presence of DON was more frequent in wheat samples, compared to oats ones (p<0.05). Extruded or toasted samples, subjected to a heat treatment during processing, presented a significantly lower concentration of OTA, and differences between the organically and conventionally produced samples were also detected in OTA, which showed higher levels in the organic samples. Co-occurrence was frequently found between the Fusarium mycotoxins (ZEA and DON). Due to the high levels of DON in the analyzed samples, a calculation of DON intake has been made and it has been demonstrated that bran can account for an important percentage of DON exposure in the total diet.